tar (computing)

Abstract: Biomass gasification for hydrogen (H2) production provides outstanding advantages in terms of renewable energy resources, carbon neutral, high efficiency, and environmental benefits. However, the factors influencing H2 production from biomass gasification are complex, which makes determining the optimal operating conditions challenging. Biomass gasification also poses challenges owing to the high associated tar content and low gas yield, which need to be overcome. This review summarizes the influence of the gasification parameters on H2 production. Catalytic gasification technology and some of the latest catalysts, such as composites and special structure catalysts, are also summarized herein based on the requirements of high-purity H2 production. Moreover, novel technologies, such as staged gasification, chemical looping gasification, and adsorption-enhanced reforming for producing H2 rich gas are introduced. Finally, the challenges and prospects associated with biomass gasification for H2 production are presented.

Abstract: Gasification and pyrolysis are thermal processes for converting carbonaceous substances into tar, ash, coke, char, and gas. Pyrolysis produces products such as char, tar, and gas, while gasification transforms carbon-containing products (e.g., the products from pyrolysis) into a primarily gaseous product. The composition of the products and their relative quantities are highly dependent on the configuration of the overall process and on the input fuel. Although in gasification, pyrolysis processes also occur in many cases (yet prior to the gasification processes), gasification is a common description for the overall technology. Pyrolysis, on the other hand, can be used without going through the gasification process. The current study evaluates the most common waste plastics valorization routes for producing gaseous and liquid products, as well as the key process specifications that affected the end final products. The reactor type, temperatures, residence time, pressure, the fluidizing gas type, the flow rate, and catalysts were all investigated in this study. Pyrolysis and waste gasification, on the other hand, are expected to become more common in the future. One explanation for this is that public opinion on the incineration of waste in some countries is a main impediment to the development of new incineration capacity. However, an exceptional capability of gasification and pyrolysis over incineration to conserve waste chemical energy is also essential.